December 11, 2018

Mars is home to a wide range of robots: orbiters, landers, and rovers. Mars may be a barren desert with no alien life — that we know of — but the planet isn’t lifeless. Thanks to Earth’s ambitious space programs, several robotic labs explore the Martian surface plus its skies.

Every 26 months there’s an opportunity to send a space vehicle from Earth to our neighboring planet Mars, in an efficient trajectory. The trip can take 6 months or more. Probes to Mars often fail. In the gallery and profile set below, you’ll learn all about the spacecraft that successfully voyaged to Mars — that are still actively exploring. NASA calls these current missions.

The average distance from our sun to a planet or moon in our solar system is measured in units called “astronomical units” — the abbreviation is AU.

One astronomical unit is about the distance from Earth to the sun. But that distance varies as Earth orbits the sun, from a maximum (called: aphelion) to a minimum (called: perihelion) — and back again, once a year.

So 1 AU is defined as approx. 93 million miles. The astronomical unit is used for measuring distances inside our solar system, or around other stars. But it’s also built-in to another measure of astronomical length — called the ParSec.

— mission: search for evidence that water once existed on Mars
— mission: search for underground deposits of water + ice
— equipped with the most powerful telescopic camera + spectrometer of all Mars spacecraft
— equipped with 6 science instruments to study the atmosphere + surface
— its instruments watch the daily weather on Mars
— the camera scopes the planet’s surface for landing sites

— twin rovers landed on Mars by parachute
— the robotic motorized rovers are equipped to study Mars geology
— discovery: both found evidence that water once existed on Mars
— Spirit stopped functioning after it was drained of power + lost in sand
— Opportunity is still exploring Mars

no. 6 | Mars Expresstype: orbiter w. landeraka: xarrived year: 2003

— the Mars Express brought along a lander called Beagle 2
— the little lander broke during its descent to the ground
— mission: exploring the atmosphere + surface of Mars from polar orbit
— discovery: spotted liquid water + ice on the planet’s south pole
— discovery: found the gas called methane Mars from geological activity inside the planet

— the ExoMars 2-part mission contains: the Trace Gas Orbiter and a lander named Schiaparelli
— the Schiaparelli lander crashed on Mars

no. 9 | InSighttype: landeraka: xarrived year: 2018

— mission: to study the deep interior of Mars
— mission: to better understand how rocky planets form
— mission: to test how effectively cube-sats can relay data from another planet

by definition | what is a space probe

A space probe is a spacecraft equipped to leave Earth on a mission to fly-by or orbit around: the sun, another planet, moon, asteroid, or meteor — or go beyond our solar system.

An impact probe is a special purpose space probe designed to deliberately crash into a planet, moon, or asteroid. Impact probes are outfitted with equipment to handle colliding with the surface. The purpose of the impact is to kick-up dust, rocks, and water found on the ground — so that the debris can be studied by on-board lab equipment.

by definition | what is an orbiter

An orbiter is a space probe designed to circle a planet, moon, or the sun — from orbit outside a planet’s atmosphere. Orbiters are also called satellites, equipped with on-board equipment to scan the surface below to detect radiation, heat, dust, water, gases — and map the topography and geology of a planet or moon. They also have advanced communications equipment to relay data back to Earth from their mission.

by definition | what is a rover -vs- lander

A rover is a robotic vehicle + mobile lab that can be operated at-at-distance from space or Earth. It can go where astronauts can’t. It’s carried by spacecraft to the moon, an asteroid, or Mars — where it lands on the surface and deploys: wheels, solar panels, remote-control devices, robotic arms + tools, antennas, cameras, communications devices.

A rover is outfitted with navigation gear — designed to travel on the surface of the moon, an asteroid, or Mars looking at terrain, checking weather, and making maps. Equipped with science instruments and electronic sensors, a rover can drive to a spot on the ground to collect samples of soil, dust, air, sunlight, water for lab studies — and take vital signs like temperature + motion. With powerful cameras it can photograph the environment. With special gear, and using satellites, it transmits information back to Earth so scientists have a close-up view — even though the moon, asteroids, and Mars are so far away.

A robotic lander is essentially the same concept as a rover — except a lander is not designed to travel on the surface of the moon, asteroids, or Mars. A lander is a stationary lab and cannot move.

Both landers + rovers are transported — from Earth to the moon, asteroids, or Mars — in the same way. Powerful propulsion rockets launch spacecraft beyond Earth’s atmosphere and orbit. The rockets separate off the spacecraft and tumble back to Earth. But the spacecraft continues on its journey to remote space destinations. The spacecraft is designed to travel long distances. It carries the lander or rover along with it — and when it arrives deploys the lander or rover so they can descend to the surface where they will stay permanently. Both landers + rovers conduct scientific experiments on the surface and are outfitted with advanced tools. And they can’t lift off, can’t fly, and can’t journey back to Earth. Also, there are no modern re-entry spacecraft that can descend to pick-up a lander or rover on the ground — and bring it home.